Microscopes are well known instruments. The focusing with upright microscopes is done by a change of the relative position of the sample on the microscope stage and the objective in the working position. This can be done by moving the turret or by moving the microscope stage on which the sample to be investigated is positioned. According to one embodiment the sample is positioned in a special slide or sample holder and the microscope stage is moved in the direction of the optical axis of the objective which is in the operating position. A focusing by moving the microscope stage is mainly done in upright microscopes.
The focusing is initiated by the user when using at least one of the operating elements provided at the microscope stand, which causes the microscope stage to move in the direction of the optical axis of the objective. In general the operating elements comprise an operating element for the fine focus and an operating element for the coarse focus. The operating elements are in the form of a rotating knob. Both rotating knobs are arranged on a common rotating axis. The rotational movement of either rotating knob is transferred into a linear movement of the microscope stage.
The operating element or the operating elements are provided at a fixed position at a side wall of the microscope stand. The operating elements are arranged at a certain distance from the support on which the microscope is placed. The arrangement of the operating elements is optimized for the average user. For users with large hands the arrangement of the operating elements is too low and for users with small hands the arrangement of the operating elements is too high. Consequently, the use of the microscope by a non-average user is not ergonomic, and is also fatiguing or may cause muscle tension.
Unpublished German patent application DE 103 40 721.9 shows a focusing device which allows a height adjustment of the focusing device. As a consequence of the height adjustment the position of the operating elements at the side wall of the microscope is changed. The position of the operating elements is adjustable to the user's ergonomic requirements and/or preferences. It has not been previously appreciated that by changing the position of the operating elements the level of the microscope stage changes as well. The range of travel of the microscope stage is shifted and this may cause damage of the slide or the microscope objective.